The present invention is directed generally to an improved flowable substance braking device and more particularly to an apparatus and method of controlling a stream of particulate matter falling in a downwardly inclining conduit.
Particulate matter, such as grain, is moved many times from its initial harvest point to its eventual processing point. Grains such as wheat, corn, soybeans, and the like are usually hauled by truck to storage bins. The grain is emptied into a pit where it is lifted by a vertical conveyor leg, passed through a distributor, down an inclining conduit, and then into a grain storage bin.
In order to accommodate several bins the vertical conveyor leg must be high enough so that the incline of the conduits running from the distributor to storage bins farthest from the leg will be steep enough for the grain to flow easily. This incline must be at least 30.degree. for dry grain, and at least 45.degree. for grain with a high moisture content.
It is apparent that the slope of the conduit to those storage containers farthest from the distributor will dictate the incline of the conduit to all other containers. Thus, those storage containers nearly abutting the leg will have conduits inclined to an almost vertical angle.
Since a kernel of grain traveling down a generally vertical conduit will fall with a negligible amount of friction its velocity may be calculated from the following expression EQU v.sub.f =.sqroot.(2gh),
where v.sub.f is the final velocity, g is the acceleration of gravity (9.8 m/s.sup.2), and h is the length of an almost vertical conduit.
The velocity of a kernel of grain will be reduced by friction forces as it travels down a conduit positioned at an incline. The acceleration of such a particle may be calculated according to the following expression EQU a=g sin .THETA.-(f/m),
where a is the particle's acceleration, g is the acceleration of gravity (9.8 m/s.sup.2), .THETA. is the incline angle of the conduit relative to the horizon, f is the frictional force, and m is the particle's mass. The velocity of such a particle may be calculated according to the following expression EQU v.sub.f =.sqroot.(2as),
where s is the length of the inclined conduit.
It can be readily observed that the velocity of the particles discharged into storage bins will depend on the proximity of the storage bin to the leg. Therefore, velocity is dependent on the length and incline of the conduit.
It is well known, to those involved in the art of handling grain, that a decrease in handling velocity means a decrease in damage to grain and grain handling equipment. It is also known that the primary source of this damage occurs from kernel-container and kernel-kernel collisions as grain is discharged from a conduit and into a storage or transport container.
Likewise, it is well known that the damage suffered by kernels is proportional to the velocity of the grain as it is discharged from conduits and into containers. Since a bushel of grain containing fractured kernels has a reduced market value it has long been the object of grain handlers to discover an economical method for reducing grain handling velocities.
Known to the art are solutions that fall within one of the following two categories. The first category of solution revolves around redesigning grain storage facilities by either reducing leg height or placing storage containers farther from the leg. Under either configuration fewer storage containers may utilize the same leg. This inherent disadvantage prevents this category of solution from being practical.
The second category of solution known to the art is also uneconomical. The devices comprising this category seek to reduce grain velocity by controlling grain flow. Prior art devices of this genre are illustrated by Wood, U.S. Pat. No. 4,159,151, Beaver, et al., U.S. Pat. No. 4,397,423, and Burnett, U.S. Pat. No. 4,342,383. All of these devices are costly to install, operate, and maintain.
Additionally, in order to reduce the velocity of particulate matter many millwrights install grain cushions 46 like that shown in FIGS. 3 and 4. Such devices 46 are fashioned by plugging the end of a piece of conduit at one end and attaching the other end 50 to the existing conduit. A hole is then made into the attached piece and another piece of conduit is welded on the attached piece as an outlet port. Particulate matter entering the device 46 first fills the chamber on the plugged end of the attached piece. Subsequent particles then bounces off of the particulate matter trapped in the plugged end before it is discharged from the outlet port.
While these devices are fairly inexpensive they wear out quickly at point 52, and particulate matter entering the device is damaged as it undergoes particle-particle collisions with particles trapped in the plugged end of the device 46.
Accordingly, a principal object of the present invention is to provide an improved method and apparatus for reducing the velocity of particulate matter
Another object of the invention is to provide a method and apparatus for controlling the velocity of particulate matter in both small and large grain handling facilities.
Still another object of the invention is to provide a method and apparatus for economically reducing the velocity of particulate matter.
Still another object of the invention is to provide a method and apparatus that is easy to install in existing grain handling facilities.
Yet another object of the invention is to provide a method and apparatus for reducing the velocity of particulate matter that will provide trouble free operation.
Yet another object of the invention is to provide a method and apparatus that is adaptable to a wide range of grain handling conditions.
Another object of the invention is to provide an apparatus that is easy to manufacture.
Another object of the invention is to provide an apparatus that does not significantly reduce the rate at which particulate matter may be handled.
Yet another object of the invention is to provide an apparatus that will increase the rate at which grain may be safely unloaded from a grain storage facility.
Yet another object of the invention is to provide an apparatus that will significantly reduce damage to particulate matter moving into and out of particulate matter storage facilities.